Nozzle construction with thermally expanding refractory insert



Sept. 12, 1967 A. E. FINN 3,341,092

NOZZLE CONSTRUCTION WITH THERMALLY EXPANDING. REFRACTORY INSERT FiledSept. 1, 1964 INVENTOR. ALFRED E. FINN United States Patent Ofiice3,341,092 Patented Sept. 12, 1967 3,341,092 NOZZLE CONSTRUCTION WITHTHERMALLY EXPANDING REFRACTORY INSERT Alfred E. Finn, Pittsburgh, Pa.,assignor to Harbison- Walker Refractories Company, Pittsburgh, Pa., acorporation of Pennsylvania Filed Sept. 1, 1964, Ser. No. 393,523 3Claims. (Cl. 222-566) The present invention relates to improved bottompour ladle nozzle construction, and more particularly to improved bottompour ladle nozzle and refractory liner insert construction.

Particularly in the manufacture of steel and steel alloys, it isconventional to tap molten metal from a furnace into a ladle in apouring pit. The pouring pit is usually at a lower elevation than thefloor on which the metal lur-gical furnaces reside, so that the moltenmetal may flow by gravity from the furnace to the ladle. Spaced from thefurnace are a plurality of ingot molds, and the ladle of molten metal ismoved through the pouring pit to a position above these ingot molds.Molten metal is poured from the ladle into the ingot molds to formingots. Usually, the metal is poured from the ladle through a nozzle,which opens through the bottom thereof. These nozzles have been thesource of many difficulties. The refractories, which are employed insuch pouring nozzles, have Worn at excessive rates or have had piecescrack and spall away, by reason of heat shock and contact with moltenmetal and slags. One of the primary problems is that these pieces ofrefractory find their way into the castings and form foreigninclusions'and flaws, which harm the quality of a final product madefrom that casting.

Heretofore and presently, the trade almost exclusively uses fireclayrefractories for these nozzles. Fire clays have been used because theyare somewhat plastic at elevated temperatures and are, therefore,expected to promote better sealing with a stopper to prevent furtherflow of the metal. However, mineralogically, fireclay refractories arenot best suited for contact with molten metal and slag. Suchrefractories are of relatively low refractoriness and have tended to berather rapidly consumed during pouring, with the eroded materiallodgingwithin the ingots. This has caused variation in nozzle orificediameter as the pouring proceeds, thereby varying pouring rate.

Accordingly, it is an-object of the present invention to provide animproved refractory pouring nozzle construction.

Another object of the invention is to provide a refractory liner insertfor use with existing refractory pouring nozzles.

A further object of the invention is to eliminate many of the problemsheretofore encountered in pouring molten metal.

Other objects of the invention will be apparent hereinafter.

In order to more fully understand the nature and objects of theinvention, reference should be had to the following detailed descriptionand drawings in which:

FIG. 1 is an elevation view partly in cross section of a bottom pourladle and nozzle assembly;

FIG. 2 is an elevation view partially in cross section of the lowerportion of a bottom pour ladle illustrating a particular embodiment ofthis invention; and

FIGS. 3a and 3b are elevation views in cross section of the bottomsection of a pouring nozzle illustrating other embodiments of theinstant invention.

Briefly, according to an embodiment of the present invention, there isprovided an improved bottom pour ladle nozzle construction. Theimprovement comprises an open ended, hollow cylindrical refractorynozzle liner insert disposed within the surface areas of the nozzle,which define the outlet of the nozzle. The refractory insert isexpandable at operating temperatures, to which the nozzle is subjectedto a degree sufiicient to provide a contiguous seat, substantiallyconforming to adjacent surface areas of the nozzle which define saidoutlet. There is also provided means cooperating with the insertdisposed exterior to, but adjacent, the outlet of the nozzle, to holdthe nozzle insert in place prior to the maintenance of said operatingtemperatures.

The refractory nozzle liner may be composed of any high qualityrefractory material, such as zircon, high alumina refractory (i.e. atleast about A1 0 by weight, is preferred), and high mangesia refractory(i.e. at least about 90% MgO, by weight). Accordingly, such a linerinsert may be employed, in combination with a pouring nozzle composed ofa relatively low quality refractory material, such as fire clay, inorder to greatly reduce erosion of the composite pouring nozzle when itis subjected to molten metal, as previously was experienced with an allfireclay refractory nozzle not having a liner insert.

Another advantage of the nozzle liner is that it is versatile, i.e. canbe fabricated and stocked in various wall thicknesses and orificediameters regardless of the dimensions of the ladle. The nozzle must fitthe ladle. The size of the liner is related to the nozzle and, as longas the outer diameter of the liner closely approximates the innerdiameter of the nozzle, the thickness and orifice of the liner can vary.In the processing of molten metals, quite often heat orders (one whichspecifies a certain pouring rate) are changed before and during tapping.A nozzle without a liner is inflexible, since it has a set orificediameter. Accordingly, when the above contingency arises, a liner havingan orifice diameter, suitable to accommodate a specific pouring rate,may be slid into the nozzle orifice without much delay. This, of course,improves the economy of the operation.

Referring to FIG. 1, there is shown a bottom pour ladle having a nozzleand liner assembly according to this invention. Such a ladle normallyincludes an outer metal shell 10 lined with a suitable refractorycomposition. The sidewalls 11 of the ladle are commonly lined withalumina-silica ladle brick,-since they are inexpensive yet satisfactoryin most instances. The bottom of the ladle includes an outer metal shell'12, also lined with a refractory composition 13, usually similar tothat which is used to line the sides. A slag lip 14 opens through aportion of the upper periphery of the sidewall and is usually fabricatedof a refractory monolith. Opening through the bottom, adjacent thesidewall, is a noZZle 15. The nozzle is lined at the outlet portion witha refractory insert 16. A downwardly extending stopper rod 17,terminating in a stopper head 18, is axially aligned with the nozzleinlet.

According to one aspect of the invention, the outer diameter of theliner insert closely conforms to the inner surface areas of the nozzlewhich define the outlet. The nozzle 16 may be temporarily seated withinsaid outlet, by use of a mortar, until the hot metal is released throughthe nozzle. Upon pouring of the metal, the heat generated will cause theinsert to sufiiciently expand and firmly seat it in place during theremainder of the pouring operation.

In FIG. 2 there is shown the bottom of the ladle of FIG. 1, illustratinganother aspect of the instant invention. After inserting the refractorynozzle liner 16, into the outlet portion of the nozzle 15, a ring-shapedmetal member 20 is disposed closely adjacent the surface areas of thenozzle, exterior of the nozzle proper, which is held in place by acantilever support. The aperture 21, in the ring member 20, is ofslightly larger diameter than the inner diameter of the liner insert andis aligned with the hollow in the insert, so that the leading edges ofthe aperture, in the ring, extend about /2 the distance of the wallthickness of the liner insert toward the hollow thereof. This is toallow the ring member to retain the insert 16, in place, until operatingtemperatures have been reached, to allow the insert to expand forpermanent seating without permitting the ring member to be exposed tothe fiow of molten metal. The ring member may be welded or otherwisejoined to a bracket 22, which is attached to a shaft 24. The shaft 24has a bent portion 25 which is seated in a hook 26, or other means, toprovide the cantilever support. The hook 26 may be secured to the ladleat the tangential joint-ure of metal shells and 12. Thu when desired,the retaining ring member may be removed from the nozzle by lifting thehandle 27 of the shaft 24 operably connected to the ring.

With reference to FIGS. 3a and 3b, there are shown other specificembodiments of the present invention. Here, the open ended, hollowrefractory nozzle liner insert 16 contains an outer peripheral flange 28at the lower end thereof. Thus, only a portion of the insert is disposedwithin the surface areas of the nozzle 15 which define said outlet. Theperipheral flange is exterior to the outlet but is contiguous to thelower end of the outlet. Metal ring members 30 and 32, having aconfiguration as shown in FIGS. 3a and 3b, respectively, are joined tothe nozzle insert 16 at the outer surfaces of flange 28 by methods wellknown in the art. Metal band members 34 and 36, as shown in respectiveFIGURES 3a and 3b and of a design particularly suited to eachapplication, are welded or otherwise joined at one end to the metal ringmembers. The other end of the metal band member contains a lip 38 thatis inserted in a peripheral groove or slot 40, at the lower end of thenozzle 15. Accordingly, the nozzle liner insert 16 is fitted .into theoutlet of the nozzle 15; and the lipped band is adjusted so that the lipportion of each band falls securely in place in the peripheral groove ofthe nozzle, to insure that the liner insert remains in place, prior tothe maintenance of temperatures sufficient to expand the liner into atight fitting relationship with the inner surfaces of the nozzle.

While the invention has been described with reference to a particularembodiment, it will be understood, of course, that modifications,substitutions, and the like may be made therein without departing fromits scope.

Having thus described the invention in detail and with sufficientparticularity as to enable those skilled in the art to practice it, whatis desired to have protected by Letters Patent is set forth in thefollowing claims.

I claim:

1. In combination with bottom pour ladle refractory nozzle construction,said nozzle having an inlet and an outlet, an open ended, hollowcylindrical refractory nozzle liner insert disposed within the surfaceareas of the nozzle which define said outlet, said refractory insertbeing expandable at operating temperatures to a degree suflicient toprovide a contiguous frictionally engaging seat substantially conforming.to adjacent surface areas of the nozzle which define said outlet andmeans cooperating with said insert disposed exterior to but adjacent theoutlet of the nozzle to temporarily hold said nozzle insert in situprior to maintenance of operating temperatures.

2. The combination with a refractory pouring nozzle having an inlet andan outlet, of an open ended, tubular refractory nozzle insert disposedwithin the surface areas of the nozzle which define said outlet, meanscooperating with the nozzle and insert arranged for temporarily holdingthe insert in place until the combination is subjected to operatingtemperature, said insert arranged to expand upon subjection to saidoperating temperature to frictionally engage adjacent surface areas ofthe nozzle and provide a positive seal against penetration of moltenmetal.

3. The combination with a refractory pouring nozzle of the fireclay typehaving an inlet and an outlet, of an open ended, tubular refractorynozzle insert disposed within the surface areas of the nozzle whichdefine said outlet, the insert fabricated of a refractory materialdifferent from the nozzle and which has a greater thermal expansion atoperating temperatures whereby to expand within said nozzle andtrictionally engage adjacent portions of said nozzle and provide apositive seal against flow of molten metal therebetween, and meanscooperating with said nozzle and insert arranged to temporarily holdthem in relative position until said insert expands at operatingtemperatures.

References Cited UNITED STATES PATENTS 1,832,873 11/1931 Milner 137-8012,424,878 7/1947 Crook 29-493 2,799,067 7/ 1957 Peterson 249202 FOREIGNPATENTS 919 11/1915 Great Britain. 948,358 1/ 1964 Great Britain.

OTHER REFERENCES Mantell, C. L, Industrial Carbon, 1946, pp. 367, 369.

I. SPENCER OVERHOLSER, Primary Examiner.

R. D. BALDWIN, Assistant Examiner,

1. IN COMBINATION WITH BOTTOM POUR LADLE REFRACTORY NOZZLE CONSTRUCTION,SAID NOZZLE HAVING AN INLET AND AN OUTLET, AN OPENING ENDED, HOLLOWCYLINDRICAL REFRACTORY NOZZLE LINER INSERT DISPOSED WITHIN THE SURFACEAREAS OF THE NOZZLE WHICH DEFINE SAID OUTLET, SAID REFRACTORY INSERTEDBEING EXPANDABLE AT OPERATING TEMPERATURES TO A DEGREE SUFFICIENT TOPROVIDE A CONTIGUOUS FRICTIONALLY ENGAGING SEAT SUBSTANTIALLY CONFORMINGTO ADJACENT SURFACES AREAS OF THE NOZZLE WHICH DEFINE SAID OUTLET ANDMEANS COOPERATING WITH SAID INSERT DISPOSED EXTERIOR TO BUT ADJACENT THEOUTLET OF THE NOZZLE TO TEMPORARILY HOLD SAID NOZZLE INSERT IN SITUPRIOR TO MAINTENANCE OF OPERATING TEMPERATURES.